The heavy load transportation is a development direction of the rail freight. At present, the heavy load mode for trains is mainly developed by the following two approaches.
(1) Increasing the axle load. However, the increase of the axle load will have influences on the operation lines of trains and bridges by which trains pass, so that the investment in the railway infrastructure construction and the maintenance cost are high.
(2) Increasing the marshalling length. This approach has the following advantages: increasing the marshalling length is simple and feasible, the existing railway equipment can be fully utilized, and the operation lines of trains and the bridges by which trains pass will not be influenced. However, the approach of increasing the marshalling length still has obvious disadvantages. The increase of the train marshalling length will increase the longitudinal impulse of trains, so that the probability of occurrence of broken coupler and derailment accidents of trains will be increased and the transportation safety of trains is thus influenced. Since the longitudinal impulse of a long marshalled train is mainly caused by “asynchronism” of front and rear portions of a train resulted from the transmission of pneumatic braking and slow-release commands via the change in train pipe pressure, this problem will become more and more serious as the marshalling length of the train, so that the transportation safety is threatened seriously and the development of heavy load transportation is restricted.
Nowadays, for a railway wagon, synchronous braking and slow-release of the whole train are realized by an electronically controlled pneumatic brake system (referred to as an ECP system hereinafter). The ECP system needs to acquire the accurate location of carriage units, and then performs accurate control and failure analysis, thereby improving the operability and safety of the train.
At present, the ECP system acquires marshalling information of the train in a manner of being connected to a switchable load to count the number of pulses. However, in this way, the marshalling time is long, the marshalling process is complicated, and the like.
An existing train marshalling device includes a Head End Unit (HEU), a telecom power system (TPS), a tail end unit, a carriage control unit, a switchable load and a current sensor for detecting the current of a carriage control power supply. The marshalling process is as follows:
1. the HEU transmits a marshalling instruction to all carriages of the train, and all carriages begin to count the number of pulses;
2. for each carriage (i) (where i=1, . . . , the serial number of a tail end carriage database),
(1) the HEU detects whether the carriage (i) is connected to a load;
(2) the HEU receives information indicating that the carriage (i) has been connected to the load;
(3) the carriage control unit detects the current of a train bus by the current sensor, and the number of pulses is added by 1 if there is pulse current; and
(4) the HEU receives information indicating that the carriage (i) has been disconnected from the load; and
3. the HEU transmits a marshalling stop instruction to all carriages of the train, and all carriages stop counting the number of pulses.
For example, with reference to the sample train marshalling device shown in FIG. 1, this train has four carriages, and the HEU repetitively performs the train scheduling process four times. During each repetition, only one carriage connects a load to the train bus to detect the presence or absence of current in each carriage and count the number of current detections. The information about the presence or absence of current and the number of current detections is stored in a “pulse counter” of each carriage. The number of pulses of the train refers to Table 1. The actual location of each carriage is based on the value of the “pulse counter” and the total number of marshalled carriages of the train.
TABLE 1IterationLoad ConnectedI1/V1I2/V2I3/V3I4/V4L4Present (1)Present (1)Present (1)Note 1L3Present (1)Present (1)Note 1Absent (0)L2Present (1)Note 1Absent (0)Absent (0)L1Note 1Absent (0)Absent (0)Absent (0)Pulse Count3210Location (the total1234carriage number-pulse numberIn Table 1, “Note 1” indicates that the number of pulses is not updated in the carriage connected to the load.
The train marshalling approach can be completed by using the existing train bus on the train, but power supply switchover needs to be performed to the train bus, and the connection to the switchable load and the disconnection from the switchable load need to be performed in each carriage of the train. Therefore, the carriage marshalling process is complicated and requires long time.